What’s the largest, least regulated, and most misunderstood drug trade in America? That would be caffeine. In his brand new book Caffeinated, investigative reporter Murray Carpenter takes a deep dive into this white-powder stimulant. The author says we underestimate nearly everything about caffeine: its prevalence in our daily lives, its health benefits, its negative impacts on our bodies and patterns. Carpenter shares a peek into his book’s most intriguing – and sometimes surprising – revelations.

Caffeine makes us act like lab rats“With caffeine – coffee and tea especially – people develop very consistent patterns,” says Carpenter. “They hit it hard early in the day and then fade off in afternoon. It’s predictable self-administration, kind of like a lab rat pushing a lever that’ll give them the next expected hit of a drug.” These patterns become so ingrained that many of us don’t even realize how long it’s been since we’ve gone without. “People go months, years, even decades without skipping caffeine a single day, which says a lot about how powerful it is,” he says.

Coffee packs way more caffeine than soda“Most caffeinated sodas have 35 to 40 milligrams of caffeine per 12 ounces,” says Carpenter. “Even if you drink five cans a day, that’s a really moderate caffeine intake compared to what most coffee drinkers consume. The caffeine in coffee is more concentrated, so even a 5-ounce cup of weak coffee has almost twice as much as a can of soda. Strong coffee could have three times the caffeine. A 16-ounce Grande coffee from Starbucks has almost as much as nine cans of soda.” Energy drinks, of course, are a different story.

One cup of strong coffee a day is enough to get you hooked“From research, we know that most people who regularly consume 100 milligrams of caffeine a day will experience withdrawal symptoms if they stop abruptly,” says Carpenter. That’s roughly three cans of soda or, depending on how strong it is, one or two cups of coffee. But even if you become dependent on caffeine, consuming a few hundred milligrams a day probably isn’t too troublesome. “For most adults, 300 to 400 milligrams a day is considered moderate, although that varies dramatically depending on your size, genetic predisposition, and many other factors,” Carpenter says. “Some people, such as smokers, process caffeine more quickly, so they need more to get the same effect.”

Overdoing caffeine can cause problems“One of the most common problems of getting too much caffeine is insomnia or sleeplessness,” Carpenter says. “But caffeine’s effect on sleep really differs from person to person. Some can drink coffee right up until they go to bed and then sleep like babies. For others, if they have caffeine after dinner, they’ll lie in bed with their heart thumping and mind wandering.” Caffeine also promotes anxiety, Carpenter says, which is already a huge problem for so many Americans. Caffeine can make it much worse. Another big issue: “Caffeine leads to a vicious circle of supplementation,” he says. “You get all jacked up on caffeine to get through the day and then have to put the brakes on hard. People often need beer or sleeping pills to wind down. Then they wake up feeling drowsier than normal, so they have to go right back to caffeine to fire up.”

It’s easy to build tolerance for caffeineNegative effects aside, there’s a reason we use caffeine – and depend on it. “Caffeine is really powerful and effective for increasing mental acuity and focus,” Carpenter says. Research shows it boosts athletic performance as well. However, these positive benefits usually wane the longer we regularly use caffeine. “Most people develop tolerance, so the coffee you drink today will not have the same effect as the first cup you ever had,” says Carpenter. But caffeine tolerance differs from that of other drugs in that you can recalibrate it. For example, an alcoholic might quit drinking for years, but if he picks it up again, he’ll usually be right back in the problem zone. Not necessarily true for caffeine. “With caffeine, you can reset your baseline pretty quickly if you quit for even a week,” Carpenter says. “You’ll go through withdrawals, but then when you start on it again, you will notice a bigger boost than you got before you quit.”

Natural caffeine is no better than synthetic“It’s really the same chemical, whether it’s carved away from an ingredient in which caffeine naturally exists, such as guarana or kola nuts, or it’s cobbled together in a laboratory,” Carpenter says. “Synthetic caffeine is cheaper and much more widely used. But if both are pure, natural-sourced and chemical caffeine should have same effects. There’s nothing wrong with natural caffeine, but there’s no additional health benefit to it. It’s more about if you don’t want your caffeine coming out of pharmaceutical plant in China.”

Caffeine isn’t required to be labeled“The Food and Drug Administration doesn’t require beverage companies to label caffeine content,” Carpenter says. “Coca-Cola, Pepsi, and Dr. Pepper do it voluntarily, although it’s in tiny print at the end of the ingredients list. You almost need reading glasses to see it.” That’s at least one good thing soda has going for it, since multiple studies have linked the sugary swill to obesity and diabetes, while diet soda is thought to mess with metabolism. “One great thing about caffeinated soft drinks is you can quantify your caffeine intake if it’s listed on the can,” Carpenter says. But labeling laws could soon change, prompted by the rapid rise of high-caffeine energy drinks. “FDA is currently wrestling with how to regulate caffeine in energy drinks,” Carpenter says. “They’re figuring out how to label caffeine count so you can look at a product quickly and see what’s in there. Labeling coffee or tea would be a much bigger challenge. However, Lipton lists how much caffeine each bag contains, and it’s pretty close to accurate.”